KOH SAMUI – The defense team for two Myanmar nationals Zaw Lin and Win Zaw Tun accused of killing two British backpackers in Thailand last year were dealt a blow on Thursday (Jul 9) when it emerged that some crucial DNA evidence would not be retested.

Crucial DNA evidence in the case of the murder of two British backpackers cannot be retested because it no longer exists, Thai police have told the BBC.

Lieutenant Colonel Somsak, who led the original investigation, said some of the original DNA samples had been “used up”.

A hair sample found in Miss Witheridge’s hand was among samples that were lost, he said.

Lieutenant Colonel Somsak said all police could offer the court was documentation of the results.

“There’s nothing left. It was used up when we tested the first time,” he said.

“The DNA samples taken from the bodies are not my responsibility. They are in Bangkok,” Police Lieutenant Colonel Somsak Nurod added.

Zaw Lin and Win Zaw Tun are on trial for the murder of 24-year-old David Miller and the rape and murder of Hannah Witheridge, 23, on Koh Tao island in September. Both have pleaded not guilty.

Thai police and prosecutors say DNA evidence points towards the two 22-year-old suspects, but the defense claims the men have been scapegoated by an under pressure police force who bungled their investigation and coerced confessions from the pair.

Much of the defense’s case revolves around a bid to retest key forensic evidence, including DNA on cigarettes and a condom found near the crime scene as well as DNA swabs taken from the victims’ bodies.

The court is due to rule Friday on whether the swabs held at Thailand’s Central Institute of Forensic Science in Bangkok may be retested, the defense team lawyer Nakhon Chomphuchart said.

“If they say (the DNA) is finished, it’s finished. Maybe our (forensic) expert will discuss on the stand whether it can be used or not. I don’t know,” lead defense lawyer Nakhon Chomphuchart said.